import cv2 as cv
import os

img_path = "img_path"  #图片所在目录
save_path = "save_path"  #转换格式后图片保存的目录
file_list = os.listdir(img_path)

for i in file_list:
    file_path = os.path.join(img_path, i)
    img_mat = cv.imread(file_path, -1)
	filename = os.path.join(save_path, i.split(".")[0] + ".png") #修改成所需要的格式后缀，如png
    cv.imwrite(filename, img_mat)